Storage and retrieval unit

ABSTRACT

The invention relates to a shelf operating device comprising at least one continuous drive element ( 13 ) which is guided about two wheels ( 12, 13 ) which are arranged at a distance from each other, also comprising an upper strand and a lower strand. At least one gripping means ( 40, 41 ) is provided in order to grip a container ( 2 ) or a pallet. The gripping means ( 40, 41 ) describes a path which extends on deflection areas of the above-mentioned ( 11, 12 ) above the path of the drive element ( 13 ). The engaging means ( 40, 41 ) is embodied in a manner similar to that of forceps and guided such that it executes a lateral movement in order to grip the container ( 2 ) or the pallet. Preferably, the gripping means ( 40, 41 ) comprises two engaging arms ( 18, 24; 18′, 24 ′) which are pivotably mounted and which can be pivoted towards each other in order to grip in a manner similar to that of forceps. Most commercially available containers ( 2 ) and pallet can be stored and removed from storage by using said shelf operating device.

The invention relates to a storage and retrieval unit for storing andremoving from store containers or pallets belonging to a rack, having atleast one endless drive element which is led around two wheels arrangedat a distance from each other and has an upper run and a lower run andon which at least one gripping means for gripping a container or apallet is arranged.

Storage and retrieval units of this type are known for picking up anddepositing loads in racks. The storage and retrieval unit is arranged ona vehicle which, for example, can be moved horizontally and verticallyon rails between racks. Using the storage and retrieval unit, containersor pallets are loaded onto the vehicle and put into store from thevehicle at the envisaged storage space in the rack. Important in suchstorage and retrieval units are a high throughput, a low demand forspace and the greatest possible precision when picking up and depositingthe containers or pallets.

A storage and retrieval unit of the aforementioned type has beendisclosed by WO 01/10751 from the applicant. This has gripping armswhich are inclined with respect to the pulling direction of the endlessdrive element and which each have a cam which moves into a verticalgroove in the pallet in order to grip a container or a pallet. As acontainer or a pallet is gripped, the cam moves into the groove frombelow. As the container or the pallet is deposited, the cam moves upwardout of the groove again. In practice, the storage and retrieval unit hasproven to be extremely worthwhile. For this storage and retrieval unit,an appropriate container or a pallet which has the aforementionedappropriate adapted groove is necessary. Previously usual containerscannot generally be used here.

EP-A-0 322 313 discloses a storage and retrieval unit in which agripping means is likewise provided which, at an outer end, has a camwhich moves into a groove in a container. Commercially availablecontainers or pallets cannot be used in this storage and retrieval uniteither. This is likewise true of the storage and retrieval unitaccording to DE-A-195 01 893. DE-A-42 33 690 discloses a storage andretrieval unit in which, in order to grip a container, a gripper engagesfully in a groove in the container. This storage and retrieval unit canonly be moved vertically between stored containers, since it wouldcollide with the containers in the event of a horizontal movement. Inaddition, this storage and retrieval unit also requires a specificcontainer.

The invention is based on the object of providing a storage andretrieval unit of the aforementioned type with which even commerciallyavailable containers or pallets can be stored and removed from store.The storage and retrieval unit is additionally to be constructionallycomparatively simple and capable of being produced economically.Nevertheless, the storage and retrieval unit is to be functionallyreliable.

In a storage and retrieval unit according to the invention, the objectis achieved in that the gripping means is formed in the manner of tongsand is guided in such a way that it carries out a lateral movement inorder to grip a container or a pallet. Using such a storage andretrieval unit, any container or any pallet that has a protruding rib ordepression at the side can be handled. By far the majority of containershave such ribs, at least on the sides, which are used here as astiffening rib. In principle, however, a frictional connection to thecontainer is also possible, so that even containers that are flat on theoutside can be stored and removed from store.

According to a development of the invention, the gripping means has twoarms mounted at a distance from each other, which carry out a pivotingmovement when gripping and depositing a container or a pallet. Accordingto a development of the invention, this pivoting movement is controlledby means of at least one rail which is fixed to a frame of the storageand retrieval unit. Two such rails are preferably provided, one railcontrolling a first gripping means and the second rail controlling asecond gripping means. The first gripping means grips a container on thepallet in order to load it onto the storage and retrieval unit, and thesecond gripping means pushes the container off the storage and retrievalunit, for example into a store. Once the container or the pallet is onthe storage and retrieval unit, it is guided by both gripping means.

According to a development of the invention, the gripping means has twogripping arms, the movement of one gripping arm being transmitted to theother gripping arm by means of a tie rod. The two gripping arms areadditionally preferably mounted on a common connecting rod. This resultsin a simple and nevertheless stable and reliable construction.

According to a development of the invention, the gripping means in eachcase have at least one rod which is positioned in such a way that itpushes the container as the latter is deposited.

Further advantageous features emerge from the dependent patent claims,the following description and the drawing.

An exemplary embodiment of the invention will be explained in moredetail in the following text by using the drawing, in which:

FIG. 1 shows in schematic form a three-dimensional view of a storage andretrieval unit according to the invention with a container,

FIG. 2 shows the view according to FIG. 1 but without a container,

FIG. 3 shows in schematic form the gripping of a container,

FIG. 4 shows a front view of the storage and retrieval unit with acontainer,

FIG. 5 shows a three-dimensional view of a gripping means,

FIG. 6 shows a further view of the gripping means according to FIG. 5,

FIG. 7 shows a further view of the gripping means,

FIG. 8 shows a section of an endless drive element,

FIG. 9 shows a further view of the section according to FIG. 8,

FIG. 10 shows in schematic form a view of the endless drive elementhaving two gripping means and

FIGS. 11 a to 11 e show in schematic form individual steps when pullinga container onto the storage and retrieval unit.

The storage and retrieval unit 1 shown in FIG. 1 is mounted on avehicle, not shown here, which can be moved in gangways in a rack inorder to pick up and deposit at least one container 2. The vehicle canalso have a plurality of storage and retrieval units 1, for example twostorage and retrieval units 1 arranged beside each other. In FIG. 1, thestorage and retrieval unit 1 is loaded with a container 2. The container2 is a normal container made of plastic and has parallel side walls 2 aand a base 2 b. Instead of the container 2, the storage and retrievalunit 1 can also be loaded with a pallet, not shown here. The container 2is used to hold the goods, not shown here, which are to be put intostore or removed from store.

According to FIG. 2, the storage and retrieval unit 1 has a frame 3which has two crossmembers 4 to which two opposite bearing plates 5 arefixed. Mounted on the bearing plates 5 is a drive shaft 7 which isdriven via a gear mechanism 8 by a motor 9, in particular an electricmotor. Also mounted on the bearing plates 5 is an axle 10 on which twochain wheels 11 are fixed, around which in each case an endless driveelement 13, for example a link chain, is placed. These two driveelements 13 are driven by the shaft 7, which likewise has two chainwheels 12. Also fixed to the frame 3 are two sliding rails 6, which arearranged at a distance from each other and run parallel to each other.These sliding rails 6 are L-shaped in cross section and are used toguide the container 2.

In order to pick up and deposit the container 2, the storage andretrieval unit has two gripping means 40 and 41, which are constructedsubstantially identically and which are fixed at a distance from eachother on the two endless drive elements 13. FIG. 5 shows the grippingmeans 40, but the gripping means 41 is constructed identically. At theends of a loadbearing rod 16 in each case a support 33 is fixed, whichis in turn fixed to two fixing lugs 37, for example screwed on.According to FIGS. 8 and 9, these fixing lugs 37 are movable connectingparts of a drive element 13. According to FIGS. 8 and 9, the driveelement 13 is an intrinsically normal link chain. However, a toothedbelt, for example, could also be used instead of the link chain 13.

On each support 33 is a gripping arm 18 and 24, respectively, which canbe pivoted to a limited extent about an axle 24 and 26, respectively. Bymeans of a tie rod 17, the two gripping arms 18 and 24 are connected toeach other. The tie rod 17 is connected to the gripping arm 24 by arotary joint 25. The tie rod 17 is connected to the gripping arm 18 by athreaded bolt 32, which is screwed into the tie rod 17 and is fixed by anut 34. Between the nut 34 and the gripping arm 18, a compression spring31, which is supported on the nut 34 and on the gripping arm 18, isarranged on the threaded bolt 32. The gripping arm 18 has a through hole42, through which the threaded bolt 32 is pushed loosely.

Also arranged on the support 33 is a pulling element 36 which can bepivoted about a rotary bearing 27. The threaded bolt 32 passes throughthe pulling arm 36 and rests with a head 32 a on the outside of thepulling element 36. Fixed to the pulling element 36 and also to thegripping arm 18 by means of fixing screws 30 is a control plate 28 and29, respectively, which in each case projects downward, as shown inparticular by FIG. 4. These two control plates 28 and 29 interact withthe control rail 19 in order to pivot the two gripping arms 18 and 24.The other gripping means 41 interacts in the same way with the otherparallel, opposite guide rail 19′.

The guide rails 19 and 19′ each have a channel 20, which is open at bothends and in which one of the two endless drive elements 13 is guided.The two gripping elements 40 and 41 are moved by the drive elements 13.By means of the guide rails 19, the gripping means 40 and 41 are in eachcase actuated one after another in such a way that the two gripping arms18 and 24 are pivoted from the spread arrangement shown in FIG. 6 in thedirection of the arrows 43 into the parallel arrangement shown in FIG.7. This is achieved by the two control plates 28 and 29 running onto thecontrol surfaces 21 running obliquely outward and shown in FIG. 6 and,as a result, being displaced in parallel. As a result, the gripping arm18 is pivoted about the rotary joint 26 and, at the same time, thepulling element 36 is pivoted about the rotary joint 27. Here, thepulling element 36 takes the threaded bolt 32 with it and, as a result,the other gripping arm 24 is pivoted into the parallel position by thetie rod 17. The compression spring 31 is tensioned hereby. In the regionof the guide rail 19, the two control plates 28 and 29 are placed on theoutside of control surfaces 22 and 23. In the region of the guide rail19, the two gripping arms 18 and 24 are thus aligned parallel to eachother, according to FIG. 7. At the other end of the guide rail 19, thetwo control plates 29 and 28 are free again and, by means of thepressure of the tensioned spring 31, these can be pivoted again into theposition shown in FIG. 6. The two gripping arms 18 and 24 are thereforespread out again. As they move onto this horizontally extending guiderail 19 or guide rail 19′, the gripping arms 18 and 24 execute atongs-like closing movement. As they leave the guide rail 19 and 19′,the tongs are opened again in opposing movements. If the gripping means40 and 41 are outside the region of the guide rail 19 or 19′, then thegripping arms 18 and 24 are opened, according to FIG. 6. Theaforementioned opening and closing is in each case carried out at theends of the guide rail 19 and 19′, specifically in each case when thegripping arms 18 and 24 are aligned horizontally.

On the two gripping arms 18 and 24, in each case at the free end, agripping finger 35 that projects inward is integrally molded. Thesegripping fingers 35 are respectively moved toward each other and awayfrom each other as the gripping arms 18 and 24 are pivoted. The distancebetween the gripping fingers 35 is thus reduced or enlarged. Thegripping fingers 35 can be designed differently. In principle, anembodiment would also be conceivable in which the gripping fingers 35are replaced by friction plates or magnets or the like.

The operation of the storage and retrieval unit according to theinvention will be explained in more detail by using FIGS. 11 a to 11 e.

In FIG. 11 a, a container 2 is ready to be picked up. The two grippingmeans 40 and 41 are located outside the region of the guide rails 19 and19′ and are therefore open according to FIG. 6. If then, from this restposition, the endless drive elements 13 are driven in the direction ofthe arrow 45, the two gripping means 40 and 41 run with it in the samedirection and ultimately reach the arrangement shown in FIG. 11 b, inwhich these extend horizontally. The gripping means 40 is in this casenot yet in engagement with the guide rail 19, and the two gripping arms18 and 24 thus remain open according to FIG. 6. The two gripping fingers35 are in each case arranged in front of a rib 39 belonging to thecontainer 2. These ribs 39 extend vertically and protrude laterally.

During an onward movement, the gripping means 40 then comes intoengagement with the guide rail 19 and, as a result, the two grippingarms 18 and 24 are pivoted and moved into the closed position shown inFIG. 7. The two gripping fingers 35 are thus moved inward toward thecontainer 2. They ultimately engage behind a rib 39 in each case andrest on the latter. The container 2 is therefore gripped by the grippingmeans 40 and is finally picked up onto the storage and retrieval unit 1,until the position shown in FIGS. 1 and 11 e is reached. In the positionaccording to FIG. 11 d, the gripping means 41 is pivoted about the axle10 and finally comes into engagement with the guide rail 19′. Thegripping arms 18′ and 24′ are therefore likewise closed in the manner oftongs and finally grip the container 2 in the position according to FIG.11 e. The container 2 has therefore been picked up onto the storage andretrieval unit 1 and is held by the two gripping means 40 and 41. Therod 17 of the gripping means 41 bears on the rear of the container 2 inFIG. 11 e. During further transport, the rod 17 pushes the container 2off the storage and retrieval unit. Once the storage and retrieval unithas been unloaded, it can be loaded with a further container. Thecontainer 2 can then be transported to the desired position by thevehicle.

In order to deposit the container 2, the drive elements 13 are movedagain, so that the container 2 in FIG. 11 e is optionally moved to theleft or to the right. If the container 2 is moved to the left in FIG. 11e, the gripping means 40 opens first. Once the gripping means 41 reachesthe drive shaft 7, this gripping means 41 is also opened and thereforethe container is released. If the container 2 is moved to the right inFIG. 11 e, the gripping means 41 opens first and finally the grippingmeans 40. During both tongs-like movements, the gripping fingers 35 ineach case describe a circular path 38, as indicated in FIG. 10 by adashed line 38. However, on account of the tongs-like movement of thegripping arms 18 and 24, such a circular path is not imperative. Thegripping arms 18 and 24 could also be guided in parallel. The two endpoints of these paths are indicated by A and B in FIG. 10. Once thegripping fingers 35 are in the region of the end points A and B, thegripping arms 18 and 24 are aligned horizontally. Outside thesepositions, the gripping arms 18 and 24 and 18′ and 24′ extendtangentially with respect to the drive shaft 7 toward the axle 10.

In order to pick up and to deposit the container 2 as explained above,only ribs 39 or recesses which protrude laterally are required on saidcontainer. Such ribs 39 are possessed by most commercially availablecontainers which are provided for storage frames. In principle, the ribs39 can also be replaced by openings or depressions. In principle, it isalso possible to grip the container 2 frictionally. This is requiredwhen the outer side of the container is flat. In this case, the grippingfingers 35 could be replaced by a rubber plate or the like. Finally, anembodiment is conceivable in which the gripping means 40 and 41 haveonly one gripping arm 18, 18′ or 24, 24′ in each case and the container2 is guided on the opposite side.

1. A storage and retrieval unit for storing and removing from storecontainers (2) or pallets belonging to a rack, having at least oneendless drive element (13) which is led around two wheels (11, 12)arranged at a distance from each other and has an upper run and a lowerrun and on which at least one gripping means (40, 41) for gripping acontainer (2) or a pallet is arranged, characterized in that thegripping means (40, 41) is formed in the manner of tongs and is guidedin such a way that it carries out a lateral movement in order to gripthe container (2) or the pallet.
 2. The storage and retrieval unit asclaimed in claim 1, characterized in that the gripping means (40, 41)has two gripping arms (18, 24; 18′, 24′).
 3. The storage and retrievalunit as claimed in claim 2, characterized in that the gripping arms (18,24; 18′, 24′) are mounted such that they can be pivoted.
 4. The storageand retrieval unit as claimed in claim 3, characterized in that thegripping arms (18, 24; 18′, 24′) are mounted on a loadbearing rod (16).5. The storage and retrieval unit as claimed in claim 2, characterizedin that the movement is transmitted from one gripping arm (18, 28′) tothe other gripping arm (24, 24′) by means of a tie rod (16).
 6. Thestorage and retrieval unit as claimed in claim 1, characterized in thatthe gripping means (40, 41) is actuated by a guide rail (19, 19′). 7.The storage and retrieval unit as claimed in claim 1, characterized inthat two gripping means (40, 41) are provided, which are each actuatedby a guide rail (19, 19′).
 8. The storage and retrieval unit as claimedin claim 2, characterized in that the gripping arms (18, 24; 18′, 24′)in each case have a gripping finger (35) at a free end.
 9. The storageand retrieval unit as claimed in claim 1, characterized in that thegripping means (40, 41) have at least one rod (17) which is positionedsuch that it pushes the container (2) as the latter is deposited. 10.The storage and retrieval unit as claimed in claim 9, characterized inthat the rod (17) is a tie rod which transmits a movement.
 11. Thestorage and retrieval unit as claimed in claim 3, characterized in thatthe movement is transmitted from one gripping arm (18, 28′) to the othergripping arm (24, 24′) by means of a tie rod (16).
 12. The storage andretrieval unit as claimed in claim 4, characterized in that the movementis transmitted from one gripping arm (18, 28′) to the other gripping arm(24, 24′) by means of a tie rod (16).
 13. The storage and retrieval unitas claimed in claim 12, characterized in that the gripping means (40,41) is actuated by a guide rail (19, 19′).
 14. The storage and retrievalunit as claimed in claim 11, characterized in that the gripping means(40, 41) is actuated by a guide rail (19, 19′).
 15. The storage andretrieval unit as claimed in claim 14, characterized in that twogripping means (40, 41) are provided, which are each actuated by a guiderail (19, 19′).
 16. The storage and retrieval unit as claimed in claim13, characterized in that two gripping means (40, 41) are provided,which are each actuated by a guide rail (19, 19′).
 17. The storage andretrieval unit as claimed in claim 16, characterized in that thegripping arms (18, 24; 18′, 24′) in each case have a gripping finger(35) at a free end.
 18. The storage and retrieval unit as claimed inclaim 15, characterized in that the gripping arms (18, 24; 18′, 24′) ineach case have a gripping finger (35) at a free end.
 19. The storage andretrieval unit as claimed in claim 18, characterized in that thegripping means (40, 41) have at least one rod (17) which is positionedsuch that it pushes the container (2) as the latter is deposited. 20.The storage and retrieval unit as claimed in claim 17, characterized inthat the gripping means (40, 41) have at least one rod (17) which ispositioned such that it pushes the container (2) as the latter isdeposited.